I am inclined to agree with Detlef that this may not be a composite piece, but fully Malay in origin. I'm not sure that you nailed the sheath ID however, since there are some more than subtle differences with the one you posted. I am a bit confused by the way the stem terminates as most that i see from the Malay side tend to have flat bottom, not this rounded end.
It would be nice to see Kai Wee or Shahrial comment here as these types of keris are really their area of study.
